Choke coil



'- Patented June 26, 19230 UNITED STATES GEORGE C. DILL, OF WILKINSBURG,

ELECTRIC & MANUFACTURING COMPANY,

PENNSYLVANIA, ASSIGNOR TO WESTINGHOUSE A CORPORATION OF PENNSYLVANIA.

CHOKE COIL.

Application filed November 0, 19191 Serial No. sacpas.

T all whom it may concern:

Be it knownthat I, Gnonon C. DILL, a citizen of the United States, and a resident of Wilkinsburg, in the county of Allegheny and State. of Pennsylvania, have invented a new and useful Improvement in Choke Coils, ofwhich the following is a specification.

My invention relates to devices for protecting electrical devices and electrical apparatus associated therewith from impulses such as are occasioned by lightning, static disturbances, and the like.

More particularly, my invention relates to choke coils that are inserted in transmission line conductors to prevent the admission of abnormally high-potential, or abnormally high-frequency surges into the ap' paratus which may be connected to the line, the coils further being devoid of ground connections or discharge paths to ground.

The object of my invention is to provide apparatus of the character designated in which the separate convolutions of the coil shall be held rigidly in position with respect to each other but not to the coilsupporting structure, and in whlch the current-carrying portions of the coil shall be entirely relieved of all mechanical strain by means of a novel structure.

In the accompanying drawings, Fig. 1 is an end elevational view of a choke coil embodying my invention, and Fig. 2 is a sectional view thereof taken in a plane at right angles to that of Fig. 1.

. Heretofore, it has been customary to support the individual convolutions of choke coils in invariable relation with respect to each other and with respect to the central or strain-insulator member by means of longitudinally extending guide members and to support the coil in the line, either by a portion of the coil conductor itself or by means of members rigidly secured to the guide members or to a portion of certain of the convolutions immediately adjacent thereto. The chief objection to the first mentioned method of support is that, when carrying a heavy-current discharge, the coil is subjected to severe mechanical, as well as electrical, strains, and, being a portion of the coil itself, this portionfrequently is deformed, sometimes preventing the proper functioning thereof. To prevent this deformation, the coil is sometimes made of exceptionally heavy material which is, of course, very ex ensive.

The chief ob ection to the latter method of support is that the coil guides frequently must withstand a considerable portion of the strains which normally should be withstood by the strain-insulator supporting member.

By my invention, I provide a device in which all portions of the coil are relieved of mechanical strains and in which the guide members serve to maintain the individual convolutions in their proper positions without taking any of the longitudinal mechanical strains for which the strain insulator is intended.

Referring to the drawings for a more detailed disclosure of my invention, I show a choke coil embodying a lurality of convolutions 3 connected to the ends 4 and 5 of a circuit in which the coil is inserted by means of end portions 6 and 7, respectively, of the coil itself. The individual convolutions are held in position by means of a plurality of circumferentially-spaced, longitudinally-extending insulating guide members 8 supported from a centrally disposed strain insulator 9 by means of arms 10 of a casting 11, these arms serving to connect the conductors 4 and 5 to the ends of the strain insulator 9. The casting 11 is connected to the strain insulator 9 by a pivotal connection 12. The arms 10 of the castings 11 are each provided, at the outer ends thereof, with a slot 13 within which the ends of the guide members 8 fit loosely. The guide members 8 are each provided with pins or bolts 14, one on each side of the arms 10 but normally spaced therefrom. These pins permit a small amount of relative longitudinal movement between the guide members 8 and the arms 10. This prevents these members from transmitting strains to each other. The convolutions 3 prevent the guide members 8 from moving out of the slots 13 in a radial direction.

From the foregoing description, it will be 'obvious that the coil, together with the guide members, is free to move a relatively small amount with respect to the central or strain insulating member, thus preventing any of the guide members 8 from assuming any portion of the longitudinal strain for which the strain insulator member is designed and which frequently reous to those skilled in the art that it is not limited, but is susceptible of various minor modifications and changes without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be imposed thereon as are set forth in the appended claims.

I claim as my invention 2- 1. A choke coil comprising a strain-resisting insulating member and a coil loosely mounted thereon and surrounding said insulating member to permit bodily movement of the coil with respect to the insulating member.

2. A choke coil comprising a strain-resist ing insulating member, a conductin coil loosely mounted thereon to permit Eodily movement of the coil with respect to the insulating member, and means for rigidl holding the convolutions of said coil in p0s1- tion with respect to each other.

3. A choke coil comprising a strain-resisting insulating member, a coil, the convolutions of which are held in spaced relation by means of circumferentially spaced supports, and means whereby said coil is loosely mounted on said strain-resisting member to permit bodily movement of the coil with respect to the insulating member.

4. A choke coil comprising a strain-resisting insulating member. a coil, the convolutions of which are held in spaced relation by means of circumferentially spaced supports, and means mounted on said strain-resisting member and engaging said spaced supports in such manner as to allow movement of said coil with respect to said strain-resisting member in a longitudinal direction.

5. A choke-coil structure comprising a strain-resisting insulating member, a coil, the convolutions of which are held in spaced relation by means of circumferentiallyspaced,

longitudinally extending guide members, and means connected to said strain-resisting member and provided with arms whereby said guide members are held in loosely supported relation with respect to said strainresisting member.

6. A choke-coil structure comprisin a coil, the convolutions of which ar hel' in spaced relation by means of circumferentially-spaced longitudinally-extending guide members, a strain-resisting member cent-rally disposed within said coil and comprising an insulating member provided with a member on each end thereof, whereby the said entire structure is supported, the said guide members being supported in such manner as to permit a relative longitudinal movement.

7 A choke-coil structure comprising a coil, the convolutions of which are held in spaced relation by means of circumferentially spaced, longitudinally extending guide members, a strain-resisting member cantrally disposed Within said coil and comprisin an insulating member provided with a spi er on each end thereof, whereby the said entire structure is supported, each of said spiders having a. plurality of radially extending arms provided with slots adjacent the outer end thereof, the said guide members being disposed within the slots of the said radially extending arms. and studs in said guide members on both sides of the casting arms.

In testimony whereof, I have hereunto subscribed my name this 30th day of Oct, 1919.

GEORGE C. DILL. 

